One of the most powerful protest songs of the 20th century, "Strange Fruit" is part of a long tradition of American protest music as old as the nation itself.

In harmony with the First Amendment's guarantee of freedom of speech, music has long been an expression of faith, freedom, peace and justice. Throughout American history, songs have cried out against inequality, poverty and war, and in support of workers, civil and human rights.

The catalog of protest music is vast. This overview highlights some of the American songs and songwriters whose words and music served as catalysts for thought, action and even social change.